As a cleaner, cheaper, and more evenly distributed fuel, natural gas has significant environmental, economic, and political advantages over petroleum as a source of energy for the transportation sector. Despite the potential benefits of natural gas, its low volumetric energy density at ambient temperature and pressure presents substantial challenges, particularly for light-duty passenger vehicles that have little extra space available for on-board fuel storage. While many commercial fleets have converted to natural gas, the vast majority of passenger vehicles continue to burn gasoline, because consumers are unwilling to sacrifice driving range, space for passengers and cargo, and convenient access to refueling stations. Adsorbed natural gas (ANG) systems have the potential to eliminate these issues by storing high densities of methane within a porous material at ambient temperature and reduced pressures. Although activated carbons, zeolites, and metal-organic frameworks have been investigated extensively for natural gas storage there are still no commercially available ANG vehicles, owing to the challenges involved in designing a practical storage system with a high capacity of usable CH4, sufficient thermal management, and a low cost.